1. Field of the Invention
The present invention relates to a data transmission system in which plural transmission channels are provided and transmission capacity and the number of lanes of transmission channels can be dynamically changed, and particularly to a highly-reliable data transmission technique capable of solving a failure.
2. Description of the Related Art
Integration of servers, storages, and networks has been progressed in racks or between racks installed in a data center, and a high throughput of tens of Tbps (terabit per second) will be required in the future. In order to realize a high throughput, there is a method of changing from electric transmission to optical transmission. However, the failure rate of optical module is high, and the reliability of the whole system is significantly deteriorated.
Under these circumstances, Japanese Patent Application Laid-Open Publication No. 2011-211532 describes a data transmission technique that can realize improvement of failure resistance in multi-lane transmission in which the number of lanes can be changed.
Further, WO 2005/10747 describes a data transmission technique in which the parity of original data transmitted from a transmitter is calculated, an error check bit between the original data and parity data is calculated, and the both are transmitted together with the original data, so that a bit error occurring in transmission channels can be corrected on the receiver side and the reliability of the transmission channels can be improved.
However, a system with the failure resistance improved can be established by the technique described in Japanese Patent Application Laid-Open Publication No. 2011-211532. However, it takes time before restoring a failure device, and thus a data loss disadvantageously occurs in the period. Further, it is difficult to detect a failure of a device in advance because the frequency and state of a failure are different depending on devices.
In addition, in the case where errors occur in even-numbered transmission channels, the errors cannot be detected and corrected by the technique described in WO 2005/10747. Further, in the case where the number of errors of transmission channels is significantly increased, the errors cannot be corrected. Furthermore, in the case where transmission channels are disconnected, it is impossible to deal with the problem.
In order to address the above-described problems, an object of the present invention is to provide a data transmission system and device in which plural transmission routes are provided and transmission capacity and the number of lanes of transmission channels can be dynamically changed, and further a highly-reliable data transmission system and device capable of immediately solving a failure.